Sensitivity of different biological responses to accumulation and depuration of butyltins in the neogastropod Thais clavigera: implications for biomonitoring.

We conducted a 3-month reciprocal transplant of the neogastropod Thais clavigera in cages between a site heavily contaminated with tributyltin and a relatively clean site to compare the sensitivity of its reproductive and physiological responses to accumulation and depuration of butyltins. Transplanting T. clavigera from the relatively clean site to the contaminated site resulted in a higher butyltin tissue concentration, higher relative penis size index (RPSI), as well as lower scope for growth (SFG) and lower Oxygen : Nitrogen (O:N) ratio. Nevertheless, growth and vas deferens sequence index (VDSI) were unaffected. Transplanting T. clavigera from the contaminated site to the relatively clean site resulted in a significant decline in tissue burden of butyltins and an elevation of scope for growth (SFG) and O:N ratio; however, there were no marked changes in growth, RPSI or VDSI. Our results thus indicated that growth is not sensitive enough for use in short-term transplant study, SFG and O:N ratio can be used as sensitive biomarkers of both accumulation and depuration of butyltins, whereas RPSI can be used only as a biomarker of accumulation of butyltins.